Stray sheep going round the ring (4)
I believe the answer is:
roam
'stray' is the definition.
(I know that stray can be written as roam)
'sheep going round the ring' is the wordplay.
'sheep' becomes 'ram' (male sheep).
'going round' is an insertion indicator (some letters go around others).
'the ring' becomes 'o' (letter resembling a ring).
'ram' going around 'o' is 'ROAM'.
(Other definitions for roam that I've seen before include "Walk without a specific destination" , "Wander freely" , "Rove or ramble" , "Peregrinate" , "Wander about aimlessly" .)